The purpose of this research is to study the process of career development. Using data from two cohorts of the National Longitudinal Surveys of Labor Market Experience, this research will quantify the extent of labor mobility of young male workers across industries and occupations in the U.S., determine how mobility differs across race/ethnic groups, and identify trends in mobility over time and across birth cohorts. Estimates of the importance of changing expectations about future wages and employment prospects in generating labor mobility and in influencing career decisions will be obtained. A comparison will be made between the importance of voluntary mobility in response to changing expectations and employer initiated layoffs in generating unemployment and career shifts. The role of exogenous aggregate shocks (such as oil shocks) in changing career patterns will be-ascertained. The extent to which the accumulation of industry- and occupation- specific skills influences the patterns of labor mobility, i.e., the extent to which employment histories matter, and affects subsequent career decisions will be estimated taking into account unobserved individual-specific differences in skills. Estimates of the influence on careers of these various factors will be obtained within a coherent theoretical framework using both approximations to optimal decision rules and exact solutions from the explicit dynamic optimization problem of the individual.